Zeolite membranes for the separation of krypton and xenon from spent nuclear fuel reprocessing off-gas

The goal of this research was to identify and fabricate zeolitic membranes that can separate radioisotope krypton-85 (half-life 10.72 years) and xenon gas released during spent nuclear fuel reprocessing. In spent nuclear fuel reprocessing, fissionable plutonium and uranium are recovered from spent nuclear fuel and recycled. During the process, krypton-85 and xenon are released from the spent nuclear fuel as process off-gas. The off-gas also contains NO, NO2, 129I, 85Kr, 14CO2, tritium (as 3H2O), and air and is usually vented to the atmosphere as waste without removing many of the radioactive components, such as 85Kr. Currently, the US does not reprocess spent nuclear fuel. However, as a member of the International Framework for Nuclear Energy Cooperation (IFNEC, formerly the Global Nuclear Energy Partnership), the United States has partnered with the international nuclear community to develop a “closed” nuclear fuel cycle that efficiently recycles all used nuclear fuel and safely disposes all radioactive waste byproducts. This research supports this initiative through the development of zeolitic membranes that can separate 85Kr from nuclear reprocessing off-gas for capture and long-term storage as nuclear waste. The implementation of an 85Kr/Xe separation step in the nuclear fuel cycle yields two main advantages. The primary advantage is reducing the volume of 85Kr contaminated gas that must be stored as radioactive waste. A secondary advantage is possible revenue generated from the sale of purified Xe. This research proposed to use a zeolitic membrane-based separation because of their molecular sieving properties, resistance to radiation degradation, and lower energy requirements compared to distillation-based separations. Currently, the only commercial process used to separate Kr and Xe is cryogenic distillation. However, cryogenic distillation is very energy intensive because the boiling points of Kr and Xe are -153 °C and -108 °C, respectively. The 85Kr/Xe separation step was envisioned to run as a continuous cross-flow filtration process (at room temperature using a transmembrane pressure of about 1 bar) with a zeolite membrane separating krypton-85 into the filtrate stream and concentrating xenon into the retentate stream. To measure process feasibility, zeolite membranes were synthesized on porous α-alumina support discs and permeation tested in dead-end filtration mode to measure single-gas permeance and selectivity of CO2, CH4, N2, H2, He, Ar, Xe, Kr, and SF6. Since the kinetic diameter of krypton is 3.6 Å and xenon is 3.96 Å, zeolites SAPO-34 (pore size 3.8 Å) and DDR (pore size 3.6 Å) were studied because their pore sizes are between or equal to the kinetic diameters of krypton and xenon; therefore, Kr and Xe could be separated by size-exclusion. Also, zeolite MFI (average pore size 5.5 Å) permeance and selectivity were evaluated to produce a baseline for comparison, and amorphous carbon membranes (pore size < 5 Å) were evaluated for Kr/Xe separation as well. After permeation testing, MFI, DDR, and amorphous carbon membranes did not separate Kr and Xe with high selectivity and high Kr permeance. However, SAPO-34 zeolite membranes were able to separate Kr and Xe with an average Kr/Xe ideal selectivity of 11.8 and an average Kr permeance of 19.4 GPU at ambient temperature and a 1 atm feed pressure. Also, an analysis of the SAPO-34 membrane defect permeance determined that the average Kr/Xe selectivity decreased by 53% at room temperature due to unselective defect permeance by Knudsen diffusion. However, sealing the membrane defects with polydimethylsiloxane increased Kr/Xe selectivity by 32.8% to 16.2 and retained a high Kr membrane permeance of 10.2 GPU at ambient temperature. Overall, this research has shown that high quality SAPO-34 membranes can be consistently fabricated to achieve a Kr/Xe ideal selectivity >10 and Kr permeance >10 GPU at ambient temperature and 1 atm feed pressure. Furthermore, a scale-up analysis based on the experimental results determined that a cross-flow SAPO-34 membrane with a Kr/Xe selectivity of 11.8 and an area of 4.2 m2 would recover 99.5% of the Kr from a 1 L/min feed stream containing 0.09% Kr and 0.91% Xe at ambient temperature and 1 atm feed pressure. Also, the membrane would produce a retentate stream containing 99.9% Xe. Based on the SAPO-34 membrane analysis results, further research is warranted to develop SAPO-34 membranes for separating 85Kr and Xe.M.S

Changes in Completed Family Size and Reproductive Span in Anabaptist Populations

The Anabaptist Amish, Hutterite and Mennonite peoples trace their origins to the Reformation. Although they share certain beliefs, such as adult baptism and the separation of church and state, each group is culturally unique. The Hutterite and Amish are highly fertile and their populations exhibit stable rates of growth. These demographic characteristics reflect communal living among the Hutterites and labor intensive farming practices among the Amish. The Mennonites are the most receptive Anabaptist group to outside socioeconomic influences and provide a demographic contrast to the more conservative Amish and Hutterites. Demographic data collected during a study of aging in Mennonite population samples from Goessel and Meridian, Kansas, 1980, and Henderson, Nebraska, 1981, formed the basis of a cohort analysis in order to assess fertility change over time. Completed family size has decreased significantly in all three communities since 1870. Since the early 1900\u27s the mean age of the mother at first birth has fluctuated but the mean age of mother at the birth of the last child is decreasing significantly for the communities of Goessel and Henderson, thus effectively shortening the reproductive span. The pattern is somewhat different for Meridian, the most conservative of the three communities

Immunoglobulin Haplotypes – Markers of Reproductive Success

Immunoglobulin haplotypes are highly polymorphic and are useful for analyses of both macro- and microdifferentiation of populations. The origins of this diversity are not known, but recent reports suggest strong selection at this locus. Increased rates of first-trimester spontaneous abortions have been reported when parents share GM phenotypes. Reduced fertility has been observed in mixed European descent white and Hutterite populations when both parents share immunoglobulin haplotypes. Population samples with completed family information and GM haplotype data are rare; the objective here is to provide this information on another sample. A sample of 242 Mennonite couples with mothers older than 40 years was divided into 3 groups of matings based on how many haplotypes were shared: 0, 1, or 2. The distribution of mean completed family sizes for the three groups were 3.35 ± 1.85 ( n = 23), 3.47 ± 1.69 ( n = 128), and 3.37 ± 1.60 ( n = 91), respectively; these values were not significantly different (F = 0.145, p = 0.865). The log-rank test was used to compare the time-to-next-birth curves. The intervals between first and later births (2-4 births) were not significantly different for the three subgroups either. There is also only limited evidence for segregation distortion in another sample of 923 offspring (in which at least one parent is heterozygous)

Patterns of DNA Methlyation across the Leptin Core Promoter in Four Diverse Asian and North American Populations

DNA methylation is the most widely studied of epigenetic mechanisms, with environmental effects recorded through patterned attachments of methyl groups along the DNA that are capable of modifying gene expression without altering the DNA sequencing. The degree to which these patterns of DNA methylation are heritable, the expected range of normality across populations, and the phenotypic relevance of pattern variation remain unclear. Genes regulating metabolic pathways appear to be vulnerable to ongoing nutritional programming over the life course, as dietary nutrients are significant environmental determinants of DNA methylation, supplying both the methyl groups and energy to generate the methylation process. Here we examine methylation patterns along a region of the metabolic gene leptin (LEP). LEP's putative functions include regulation of energy homeostasis, with its signals affecting energy intake and expenditure, adipogenesis and energy storage, lipid and glucose metabolism, bone metabolism, and reproductive endocrine function. A pattern of differential methylation across CpG sites of the LEP core promoter has been previously identified; however, any consistency of pattern or its phenotypic significance is not fully elucidated among populations. Using DNA extracted from unfractionated white blood cells of peripheral blood samples, our pilot study, divided into two parts, examined the significance of variation in DNA methylation patterns along the leptin core promoter in four populations (phase 1) and used biomarkers reflecting leptin's functional process in two of those populations, western Buryat of Siberia and the Mennonite of central Kansas, to investigate the relevance of the ethnic variation identified in the DNA methylation (phase 2). LEP's core promoter region contains both the binding site for C/EBPα (CCAAT/enhancer binding protein alpha), which tempers the final step in adipocyte maturity and capacity to synthesize leptin, and the TATA motif controlling leptin synthesis. Previous studies report that increased methylation in this region is correlated to decreased gene expression, suggesting tissue-specific methylation variation at this region (Melzner et al. 2002). We hypothesized that evidence of nutritional epigenetic programming would be identified through variation in patterns of DNA methylation and that functional relevance of that variation among populations would be identified through biomarkers that reflect leptin's metabolic signals: serum leptin levels, lipoproteins of the lipid transport system, and anthropometric measures. In phase 1, our combined analyses of 313 individuals documented a distinct and consistent overall pattern of differential DNA methylation across seven CpG sites of LEP core promoter in all ethnicities and both sexes. This pattern replicates those identified in previous studies, suggesting a conserved core promoter region across populations. Phase 2 analyses of two of the four populations (n = 239), correlating methylation at the C/EBPα transcription binding site (TBS) with metabolic and anthropometric biomarkers reflecting LEP roles, showed that stature, which reflects bone growth and remodeling, was significantly and inversely correlated with the percentage of DNA methylation at this site in both sexes. We suggest that variation in DNA methylation along the LEP core promoter plays a substantial role in energy signals affecting both adipogenesis and bone metabolism

Mitochondrial DNA Diversity in Mennonite Communities from the Midwestern United States

We examined mitochondrial DNA (mtDNA) variation in six Mennonite communities from Kansas (Goessel, Lone Tree, Garden View, Meridian, and Garden City) and Nebraska (Henderson) to determine their genetic structure and its relationship to population history. Mitochondrial DNA haplogroup and haplotype information were obtained from blood samples from 118 individuals. Molecular genetic variation was analyzed using diversity measures, neutrality test statistics, spatial analysis of molecular variance (SAMOVA), and multidimensional scaling plots. The Mennonite samples exhibited eight western European mtDNA haplogroups: H, HVO, I, J, K, T, U, and X. Comparable to other populations of European descent, haplogroup H was the most frequent in all six communities and ranged from 35% in Lone Tree to 75% in Old Order Mennonites from Garden City. Fifty-eight different mtDNA haplotypes were found in these groups with only one shared among all six populations. Haplotype diversities varied from 0.81 in Goessel to 0.96 in Henderson and Garden View. Multivariate statistical analysis of these populations indicates that these Anabaptist communities formed new congregations by fissioning along familial lines. Population subdivision of these communities into congregations supports previously documented patterns of fission-fusion. These haploid molecular data provide a more accurate reflection of biological relationships between midwestern Mennonite communities than evidence based on classical genetic markers

2002-2003 Third Annual Mozart Birthday Concert

https://spiral.lynn.edu/conservatory_otherseasonalconcerts/1078/thumbnail.jp

Relationship of Metabolizable Protein Balance, Purine Derivative Excretion, and 3-Methyl Histidine Excretion to Feed Efficiency in Individually Fed Finishing Heifers

Individually fed heifers were used to determine the relationship of 3-methyl histidine, purine derivatives, and metabolizableprotein balance to feed efficiency. Heifers were fed finishing dietsthat were either deficient or sufficient in metabolizable protein. Urine samples were collected and analyzed for early, late, and entire feeding period concentrations of 3-methyl histidine, purine derivatives, and creatinine. Results from this study indicated a negative relationship between feed efficiency and metabolizable protein balance, and no relationship between 3-methyl histidine excretion and feed efficiency, suggesting that protein turnover and microbial protein synthesis are not related to feed efficienc

Relationship of Metabolizable Protein Balance, Purine Derivative Excretion, and 3-Methyl Histidine Excretion to Feed Efficiency in Individually Fed Finishing Heifers

Individually fed heifers were used to determine the relationship of 3-methyl histidine, purine derivatives, and metabolizableprotein balance to feed efficiency. Heifers were fed finishing dietsthat were either deficient or sufficient in metabolizable protein. Urine samples were collected and analyzed for early, late, and entire feeding period concentrations of 3-methyl histidine, purine derivatives, and creatinine. Results from this study indicated a negative relationship between feed efficiency and metabolizable protein balance, and no relationship between 3-methyl histidine excretion and feed efficiency, suggesting that protein turnover and microbial protein synthesis are not related to feed efficienc

Discovering sequences with potential regulatory characteristics

AbstractWe developed a computational model to explore the hypothesis that regulatory instructions are context dependent and conveyed through specific ‘codes’ in human genomic DNA. We provide examples of correlation of computational predictions to reported mapped DNase I hypersensitive segments in the HOXA locus in human chromosome 7. The examples show that statistically significant 9-mers from promoter regions may occur in sequences near and upstream of transcription initiation sites, in intronic regions, and within intergenic regions. Additionally, a subset of 9-mers from coding sequences appears frequently, as clusters, in regulatory regions dispersed in noncoding regions in genomic DNA. The results suggest that the computational model has the potential of decoding regulatory instructions to discover candidate transcription factor binding sites and to discover candidate epigenetic signals that appear in both coding and regulatory regions of genes

Cyclist and pedestrian trust in automated vehicles: an on-road and simulator trial

Automated vehicles (AVs) need to be trusted by cyclists and pedestrians where they will share the road. To test trust, cyclists and pedestrians, and a comparison cohort of drivers, observed trials of both a road and simulator AV undertaking three common priority-based maneuvers: a right turn into a side road, overtaking a parked car, and passing over a pedestrian priority (zebra) crossing. The AV made the maneuvers either giving way, or not giving way, to a pedestrian or cyclist. One hundred and thirty-four participants aged 18 to 79 years were recruited based on being predominantly either a pedestrian, cyclist, or driver in their regular road use. For the on-road trials, the cyclist and pedestrian participants observed the AV maneuvers from the adjacent footway, and the driver participants observed from inside the AV. In the simulation environment, all participants were inside the automated vehicle. Trust scores were higher when participants observed a maneuver where the AV had to give way to a cyclist, and this can be linked with the re-assurance provided by the behavior of the AV in such an encounter. There was no significant difference in trust by road user type (cyclist, pedestrian or driver), age or driving experience, suggesting messaging to road users about the impacts of automated vehicles need not be differentiated by road user type. There was some evidence of differences in trust, especially for more complex maneuvers, between the on-road trial and the simulator, suggesting a need for caution in reliance on simulation-only experiments